DUPLEX STAINLESS STEEL HAVING EXCELLENT CORROSION RESISTANCE WITH LOW NICKEL

摘要

Disclosed is duplex stainless steel that contains relatively low content of Ni, and limits constituents of Cr-Mo-Mn-N to make volume fraction of a and ? have about 50:50, thereby minimizing incidence of a edge crack to enhance a production yield and decrease a processing load, in which the alloy constituents includes Cr of 19.5 ~ 22.5%, Mo of 0.5-2.5%, Ni of 1.0-3.0%, Mn of 1.5-4.5%, N of 0.15-0.25%, Fe and unavoidable elements, and a constitution range of the alloy constituents are adjusted to make a CPT highter than 20°C depending on the constitution range of the alloy constituents. Thus, the contents of Cr, Mo and Ni is decreased and the content of Mn is increased a little, so that a production cost thereof is reduced; the corrosion resistance is secured to be better than the STS 304 steel and the 316L steel; the incidence of the edge cract is decreased while being hot-rolled, thereby decreasing a load on the following process; and the surface defective is decreased, thereby improving a production yield.